Convert Dan/Picul to troy ounces

A load, then a number

Like most bulk units, the dan began as a physical description rather than a measurement: it was what a labourer could carry on a shoulder pole, a load split into two baskets. Standardising it at one hundred catty turned a human capacity into an accounting quantity, and once the catty had a legal value the dan inherited it automatically.

The English word "picul" reached shipping documents through Malay, which is why nineteenth-century bills of lading from Canton, Batavia and Singapore all use it while the Chinese originals say dan. Any archival trade figure in piculs should be converted using the value in force at that port and period, not a modern figure.

The mainland and Hong Kong values

The mainland market system sets the jin at exactly 500 grams, so a dan of one hundred jin is exactly 50 kilograms. Hong Kong retains the catty at 604.78982 grams, making its picul 60.478 kilograms. That is a twenty percent difference on the same word, and on a container-scale shipment it is a commercially decisive gap.

Chinese agricultural statistics — grain yields, tea production, cotton output — are published in dan on the mainland basis. Reading a yield figure in dan per mu and converting with the Hong Kong value inflates the result by a fifth, which is enough to make a normal harvest look exceptional.

Where it still appears

Tea is the most visible surviving use. Wholesale pu-erh and oolong are still discussed in dan and catty in the Chinese trade, and cake sizes are set in Chinese units even when the export label prints grams. Dried seafood, herbs and rice move the same way through traditional wholesale markets in Hong Kong, Guangzhou and Southeast Asia.

Modern contracts increasingly state both a dan figure and its metric equivalent, which is good practice and worth insisting on. Where only the traditional figure appears, the safest reading is to identify the seller's jurisdiction, apply that jurisdiction's catty, and record the assumption in the file — because a dispute over a twenty percent discrepancy is unresolvable after the fact if nobody wrote down which system was intended.

Historical series and the picul

Long-run Chinese commodity series — tea exports, grain tribute, cotton output — are usually compiled in dan, and the underlying catty changed across the period they cover. A single conversion factor applied to a series spanning the Qing, Republican and post-1949 eras merges at least three different standards into one line.

The workable method is to convert in segments, with the standard in force for each, and to note the break points in whatever is published. Where a source does not state its basis, the surrounding trade documents usually do: bills of lading and customs returns from the same port and period are the most reliable evidence of which catty the compiler assumed.

The character is also read as shi in some contexts and as picul in English-language sources, and all three refer to the same unit. A bibliography that treats them as distinct measures will double-count, which is a recurring problem in secondary literature on the China trade.

Common mistakes to avoid

• Mainland dan is exactly 50 kg; Hong Kong picul is 60.478 kg — a 20% gap on the same word.
• Chinese agricultural statistics use the mainland value; converting them with the Hong Kong catty inflates yields by a fifth.
• Historical picul figures in colonial shipping records follow the port standard of their period, not any modern value.
• A contract that states only "dan" without a jurisdiction or a metric equivalent is genuinely ambiguous.

Questions people ask about the Dan/Picul

How many kilograms is one dan or picul?

Exactly 50 kg in the mainland Chinese market system (100 jin of 500 g). In Hong Kong the picul is 60.478 kg, because the Hong Kong catty is 604.78982 g.

Is dan the same as picul?

Yes. "Picul" is the English and Malay trade name for the Chinese dan, a load of one hundred catty. Colonial-era shipping documents use picul where the Chinese originals use dan.

What is a dan used for today?

Chinese grain, tea, cotton and dried-goods trade still quotes in dan, and mainland agricultural statistics publish yields in dan per mu. Modern contracts usually state a metric equivalent alongside it.